The present invention relates generally to locking adjustment mechanisms for steering columns and more specifically to systems and methods for selectively fixing a position of a steering column assembly or facilitating adjustment of a steering column assembly in at least a raking direction.
Traditional locks for steering columns often provide inadequate load handling capabilities for preventing upward steering column displacements in the event of a vehicle collision. Some prior attempts to address this issue have sought use of interlocking teeth to provide the required vertical stability. Unfortunately, however, many configurations that employ interlocking teeth to provide for a positive lock, while providing for selective engagement and disengagement of the teeth for alternating adjustment and locking of the steering column, encounter practical difficulties. For example, one source of dissatisfaction with such locking mechanisms is that the need to interlock the teeth of one component with the teeth of another may limit the available lock positions to a predefined finite set of positions. This issue provides a motivation toward decreasing the size of each of the teeth so as to decrease the incremental difference from one position to the next, providing for finer adjustments. Unfortunately, smaller teeth can result in decreased position assurance and loss of tactile sensations normally associated with the failure to securely seat the interlocking teeth.
Other proposed solutions involve the use of frictions locks, which may provide more fine adjustments, but may sacrifice reliability, being susceptible to unintended releases (e.g., sliding adjustments, creep) under some loads.
Accordingly, it is desirable to have a system and method for selectively fixing and adjusting a position of a steering column with improved fineness in the availability of adjustment positions and with improved reliability and security.